Device and method for controlling an automatic steering system of a vehicle, and device and method for checking the ability to implement a predefined setpoint travel direction variable for a vehicle

Abstract

A device for controlling an automatic steering system of a vehicle includes a signal input (which receives a setpoint travel direction variable, a memory device on which a correction factor is stored, a control unit which ascertains a corrected setpoint travel direction variable on the basis of the correction factor and the predefined setpoint travel direction variable, and an evaluation device which compares an actual travel direction variable ascertained by a sensor of the vehicle to the predefined setpoint travel direction variable, and if the actual travel direction variable deviates from the predefined setpoint travel direction variable by at least a minimum difference, redefines the correction factor according to the comparison.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a device and a method for controlling an automatic steering system of a vehicle and particularly relates to a device and a method for checking the ability to implement a predefined setpoint travel direction variable for a vehicle.2. Description of the Related ArtProviding vehicles with an automatic vehicle control system is known. An automatic lane departure warning system or a parking assistance system is an example of such an automatic vehicle control system. To assist the driver in parking in a parking space, the parking assistance system ascertains an advantageous parking trajectory, taking into account the dimensions of the parking space and a position of the vehicle in relation to the parking space. For example, the parking trajectory is made up of a consecutive series of linear segments, circular segments, and clothoids. Depending on the dimensions and the starting positions, the circular seg...

AI Technical Summary

Benefits of technology

The device and the method provide compensation for offsets which during a semi-automatic parking maneuver may be caused by the electronic steering system installed in the vehicle. The robustness of semi-automatic parking systems may thus be improved via the present invention. Independent adaptation of the system to the connected sensor system and actuator system is possible. Aging processes or other influencing factors on the automatic steering system or on the translation of the steering angle into a position of the wheels may thus be compensated for. The present invention may be implemented at low cost.

In one advantageous refinement, the evaluation device is also designed to limit the possible causes for the deviation of the at least one actual travel direction variable from the at least one predefined setpoint travel direction variable by the at least one minimum difference by comparing the actual steering wheel angle to the setpoint steering wheel angle, and by comparing the actual wheel angle to the setpoint wheel angle. If, for example, the actual steering wheel angle corresponds to the setpoint steering wheel angle, it may be ruled out that the deviation of the actual wheel angle from the setpoint wheel angle is caused by a malfunction of the automatic steering system. The cause of error may be ascertained in particular by comparing multiple actual values to multiple setpoint values. This reduces the costs for eliminating the deviation.

In another advantageous refinement, the device has a further signal input which is designed to receive a vehicle inclination ascertained by a further sensor of the vehicle and / or a coefficient of friction of a traveled roadway ascertained by a further sensor of the vehicle, the control unit being designed to read out from the memory device, from a predefined set of correction factors, a correction factor which corresponds to the vehicle inclination and / or the coefficient of friction of the traveled roadway. This allows the corrected setpoint travel direction variable, and thus the corresponding actual travel direction variable, to be adjusted to weather conditions and environmental conditions.

The device may also be designed in particular to limit the possible causes for the deviation of the at least one adjustment force from the at least one comparative value by the at least one minimum difference by comparing multiple adjustment forces to multiple comparative values. In particular, the device is able to identify the probable cause by comparing multiple adjustment forces to multiple comparative values, which facilitates elimination of the cause.

Problems solved by technology

In addition, aging processes or wear processes in the automatic steering system or the chassis may result in imprecise setting of the predefined setpoint travel direction variable.

Other customary sources of errors are manufacturing tolerances and external influences on, or changes to, the chassis.

Thus, repeatedly driving up against a curb, which generally occurs with extended operation of a vehicle, results in mechanical misalignments of the chassis.

In addition, changing the tires of the vehicle may result in deviations in the set steering angle from a predefined setpoint wheel angle.

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